“The Exterior Tricomi and Frankl Problems for Quaterelliptic-Quaterhyperbolic Equations with Eight Parabolic Lines” (2011) European Journal of Pure and Applied Mathematics, 4(2), pp. 186–208. Available at: https://www.ejpam.com/index.php/ejpam/article/view/1175 (Accessed: 24 November 2024).